The invention generally relates to a digital X-ray detector assembly, and in particular to digital X-ray detector panels.
The use of digital radiological imaging continues to be invaluable with respect to a variety of technical applications. Digital radiological imaging is a mainstay in the medical field allowing health care professionals to quickly discern and diagnose internal abnormalities of their patients. Additionally, its use has become increasingly important in industrial fields for visualizing internal contents of parts, baggage, parcels, and other objects, and for visualizing the structural integrity of objects and other purposes. Indeed, the evolution of digital X-ray detectors has enhanced both workflow and image quality in the field of radiological imaging.
Generally, radiological imaging involves the generation of X-rays that are directed toward an object of interest. The X-rays pass through and around the object and then impact an X-ray film, X-ray cassette, or digital X-ray detector. In the context of the digital X-ray detector, these X-ray photons traverse a scintillator that converts the X-ray photons to visible light or optical photons. The optical photons then collide with the photo detectors of a digital X-ray receptor and are converted to electrical signals which are then processed as digital images that can be readily viewed, stored, and/or transmitted electronically.
The conversion factor (CF) is a quality measurement of digital X-ray detectors that is generally recognized in the industry. It is defined as the number of electrons generated by the detector per incident X-ray photon. The value of CF varies depending on the energy of the X-ray photon as well as the light efficiency of the X-ray detector.
In low dose applications, such as fluoroscopic imaging, CF is generally higher than some other applications to reduce the impact of electronic noise. In high dose applications such as radiographic imaging, however, we need to control the CF in order to cover a required dynamic range of radiation dosage.
Considering the variability of CF for the various applications, each application requires a dedicated detector type because for a given X-ray photon energy, existing X-ray detectors have a fixed CF. In X-ray systems, such as a Radiography and Fluoroscopy (R&F) system, for instance, a value of CF is generally selected to balance the low dose performance in fluoroscopic imaging and the dynamic range in radiographic imaging. As a result, the compromised value of CF is neither optimal for fluoroscopic imaging nor radiographic imaging. Consequently, there is still a need for a technology that is able to change the value of CF in a single detector on demand in order to accommodate the various digital radiological imaging applications.
It has been determined that by placing a light attenuator between the X-ray scintillator and the light imager of an X-ray detector panel and applying varying voltage across the one or more pairs of electrodes of the light attenuator, the CF can be dynamically controlled and allow a single X-ray detector to accommodate multiple applications of digital radiological imaging.
It has also been determined that a light attenuator made of core material surrounded by clad material that is the same or similar to a fiber optic plate (FOP) helps prevent light photons from laterally spreading through the light attenuator and therefore improving the spatial resolution of the X-ray detector.
It has also been determined that by utilizing a two-dimensional (2D) pixel array with a light attenuator, the CF of the X-ray detector can be controlled by changing the light transmission rate of the light attenuator locally on a pixel by pixel basis, and thereby preserve the skin line of the anatomy and eliminate image burnout.